Read data from an Adafruit Trinket over USB

ReadSensor.java

import java.nio.*;
import org.usb4java.*;

public class ReadTrinket {
    public static void main(String args[]) {
        Context context = init();
        DeviceHandle trinketHandle = openDevice();

        try {
            int result = LibUsb.claimInterface(trinketHandle, (short) 0x00);
            if (result != LibUsb.SUCCESS) throw new LibUsbException("Cannot open Trinket interface", result);

            try {
                System.out.println("Found Trinket, Data: ");
                for(int i=10; i >= 0; --i)
                    System.out.println(read(trinketHandle, 5000));
            } finally {
                result = LibUsb.releaseInterface(trinketHandle, (short) 0x00);
                if (result != LibUsb.SUCCESS) throw new LibUsbException("Failure releasing Trinket interface", result);
            }

        } finally {
          LibUsb.close(trinketHandle);
        }

        LibUsb.exit(context);
    }

    public static Context init() {
      Context context = new Context();
      int result = LibUsb.init(context);
      if (result != LibUsb.SUCCESS) throw new LibUsbException("Unable to initialize libusb", result);
      return context;
    }

    public static DeviceHandle openDevice() {
      Device trinketDev = findDevice();
      DeviceHandle trinketHandle = new DeviceHandle();
      int result = LibUsb.open(trinketDev, trinketHandle);
      if (result != LibUsb.SUCCESS) throw new LibUsbException("Cannot find Trinket", result);
      return trinketHandle;
    }

    public static Device findDevice() {
        short vendorId = 0x1781;
        short productId = 0x1111;

        DeviceList list = new DeviceList();
        int result = LibUsb.getDeviceList(null, list);
        if (result < 0) throw new LibUsbException("Unable to fetch device list", result);

        try {
            for (Device device: list) {
                DeviceDescriptor descriptor = new DeviceDescriptor();
                result = LibUsb.getDeviceDescriptor(device, descriptor);
                if (result != LibUsb.SUCCESS) throw new LibUsbException("Failure in reading device", result);

                if (descriptor.idVendor() == vendorId && descriptor.idProduct() == productId) return device;
            }
        } finally {
            LibUsb.freeDeviceList(list, true);
        }

        return null;
    }

    public static String read(DeviceHandle handle, long timeout) {
        byte endpointId = (byte) 0x81;
        StringBuilder stringBuilder = new StringBuilder();
        boolean started = false;

        while(true) {
            ByteBuffer buffer = BufferUtils.allocateByteBuffer(2).order(ByteOrder.LITTLE_ENDIAN);
            IntBuffer transferred = BufferUtils.allocateIntBuffer();
            int result = LibUsb.bulkTransfer(handle, endpointId, buffer, transferred, timeout);
            if (result != LibUsb.SUCCESS) throw new LibUsbException("Failure reading data", result);

            CharBuffer charBuffer = buffer.asCharBuffer();
            while(charBuffer.hasRemaining()) {
                char nextChar = charBuffer.get();
                if(nextChar == '\n') started = true; //Start Character
                else if(nextChar == '\r' && started) return stringBuilder.toString(); //End Character
                else if(started) stringBuilder.append(nextChar);
            }
        }
    }
}

ReadSensor.py

#!/usr/bin/python

import sys, time, getopt, subprocess
import usb.core, usb.util
import logging
import inspect

logging.basicConfig()
logger = logging.getLogger()
logger.setLevel(10)

class Sensor:
    trinket = False
    endpoint = 0x81

    def __init__(self):
        self.reconnect()

    def __del__(self):
        self.trinket = False

    def reconnect(self):
        self.trinket = self.__findTrinket()

        if self.trinket != False:
            self.endpoint = self.trinket[0][(0,0)][0]
            logger.info("Button Ready");

    def readline(self):
        if not self.trinket:
            logging.error('No trinket connected, trying again...')
            self.reconnect()
            return self.readline()

        try:
            char_buffer = ''
            while True:
                data = self.trinket.read(self.endpoint.bEndpointAddress, self.endpoint.wMaxPacketSize)
                readCnt = len(data)
                if readCnt > 0:
                    char_buffer += bytearray(data)
                    if '\r\n' in char_buffer[-2:] and len(char_buffer.strip()) > 0:
                        return char_buffer.strip()

        except Exception as ex:
            exStr = str(ex).lower()
            if 'timeout' not in exStr:
                logging.error('USB read error', ex)
                self.trinket = False

    def __findTrinket(self):
        device = usb.core.find(idVendor = 0x1781, idProduct = 0x1111)
        if device == None or device == False or device == 0 :
            return False

        device.set_configuration()
        return device

sensor = Sensor()
while True:
    print sensor.readline()

SendSensor.ino

#include "TrinketFakeUsbSerial.h"

void setup()
{
  TFUSerial.begin();
  pinMode(1, OUTPUT);
  pinMode(2, INPUT);
}

void loop()
{
  TFUSerial.task();

  analogWrite(1, analogRead(1));

  TFUSerial.println(analogRead(1));
}